Refarming 10 meter FM?

[WA4ILH]

OK, ... it's Friday and maybe I'm bored but I was thinking (possibly my first mistake) ...with the newer "Narrow Band" FM radios (+/- 2.5 Khz deviation) it would be possible and legal to transmit NB FM below 29.5 Khz. (actually 29.3 Khz since the subband 29.3-29.510 is reserved for satellite comms) Why not phase in a new FM band plan to incorporate this new technology? We could refarm the 10 meter FM repeater sub-band to incorporate 10 Khz channel spacing, at least double the number of repeater pairs and slide the FM band down to just above 29.2 Mhz. (29.2 Mhz is "AM territory".) I don;t know anything about low band repeaters and how they achieve an acceptable frequency separation of only 100 Khz between input and output but maybe somehow they could increase the separation in the process?
Tom WA4ILH

[K7JEM]

OK, ... it's Friday and maybe I'm bored but I was thinking (possibly my first mistake) ...with the newer "Narrow Band" FM radios (+/- 2.5 Khz deviation) it would be possible and legal to transmit NB FM below 29.5 Khz. (actually 29.3 Khz since the subband 29.3-29.510 is reserved for satellite comms) Why not phase in a new FM band plan to incorporate this new technology? We could refarm the 10 meter FM repeater sub-band to incorporate 10 Khz channel spacing, at least double the number of repeater pairs and slide the FM band down to just above 29.2 Mhz. (29.2 Mhz is "AM territory".) I don;t know anything about low band repeaters and how they achieve an acceptable frequency separation of only 100 Khz between input and output but maybe somehow they could increase the separation in the process?
Tom WA4ILH

The FCC rules define where repeaters can operate. Currently, that band is from 29.5 to 29.7, which means that it would take a rule change to have repeaters below that point.

And yes, 2.5KHz deviated FM is actually allowed most places phone is allowed on HF, you could use it on 28.6 or 21.340 if you wanted.

Joe

[WA4ILH]

The FCC rules define where repeaters can operate. Currently, that band is from 29.5 to 29.7, which means that it would take a rule change to have repeaters below that point....


Joe

Forgive me Joe but where does it say that? I found where it says that all FM with a modulation index greater than 1 must be above 29.5 Mhz ...
Tom WA4ILH

[N8YX]

Solution looking for a problem. In most areas, there isn't enough of a demand for new 10M repeaters to warrant a rule change...

[WG7X]

Solution looking for a problem. In most areas, there isn't enough of a demand for new 10M repeaters to warrant a rule change...

Exactly!

Please Mr. Sun, give us some spots!



Gary

[WA4ILH]

OK, I found the 29.5 Mhz reference. 47 CFR 205(b). I stand corrected. It would require a rules change. (I was looking in the emissions standards section) Still, a rules change is doable.
Tom WA4ILH

[K7JEM]

Forgive me Joe but where does it say that? I found where it says that all FM with a modulation index greater than 1 must be above 29.5 Mhz ...
Tom WA4ILH

§ 97.205 Repeater station.

(b) A repeater may receive and retransmit
only on the 10 m and shorter
wavelength frequency bands except the
28.0–29.5 MHz,

And the mod index thing starts above 29.0 MHz, not 29.5.

Joe

[AB8ZL]

Forgive me Joe but where does it say that? I found where it says that all FM with a modulation index greater than 1 must be above 29.5 Mhz ...
Tom WA4ILH

I believe it says that FM with a modulation index greater than 1 must be above 29.0 MHz, not 29.5MHz.

97.205(b) is where the FCC states where repeaters are allowed to operate.

“A repeater may receive and retransmit only on the 10 m and shorter wavelength frequency bands except the 28.0-29.5 MHz, 50.0-51.0 MHz, 144.0-144.5 MHz, 145.5-146.0 MHz, 222.00-222.15 MHz, 431.0-433.0 MHz and 435.0-438.0 MHz segments.”

[WB2WIK]

I work 10m FM "simplex" below 29.5 MHz all the time. We don't have any U.S. repeaters below 29.5, but that doesn't mean you can't transmit there using conventional (5 kHz deviation) FM.

For example, the "simplex calling frequency" in Japan is 29.300 (not 29.600 like here in the States). When the band's open, that frequency is very busy!

WB2WIK/6

[K9STH]

Using FM is legal under FCC rules on all frequencies that phone operation is allowed except for the 5 channel 60 meter band which is USB only. The restriction is that below 29.0 MHz the modulation index cannot exceed 1 which generally means that the deviation cannot exceed +/- 3 kHz (when the maximum modulating frequency is 3000 Hz). Above 29.0 MHz the modulation index can exceed 1. For example, running +/- 5 kHz deviation on 29.600 MHz with a maximum modulation frequency of 3000 Hz produces a modulation index of 1.66667.

However, it is illegal for someone holding either a Technician Class or Novice Class license to use FM in the 10 meter band because those two license classes are limited to SSB ONLY in the 28.3 MHz to 28.5 MHz segment. Although General Class, Advanced Class, and Amateur Extra Class licensees can use FM in the 28.3 MHz to 28.5 MHz segment it is blatantly illegal for Technician Class or Novice Class licensees to use that mode.

As was pointed out by several, repeater operation in the 10 meter band is limited to 29.5 MHz to 29.7 MHz by FCC regulations.

Glen, K9STH